Many individuals in health care facilities are able to achieve sufficient caloric intake through eating prepared meals. However, a sizable number of such patients are unable to ingest enough food to meet their body's needs. Examples of these individuals would include burn patients, whose daily caloric needs are often in excess of 5,000 calories, and critically ill, weak, or comatose patients who may be unable to chew their food. For these patients, caloric supplementation through parenteral, also known as intravenous, feeding is not a viable alternative.
In response to this problem, liquid foods have been developed for enteral feeding. Enteral feeding is providing nourishment through the oral tract by defined nutritional diets. Typically, enteral feeding utilizes a nasogastric tube to transport the liquid nutritional products from the container through the patient's nasal cavity and thence into the stomach. Early enteral nutritional product containers were empty, sterilized pouches which were filled with sterilized, canned product at the point of use. The filled pouch was ultimately spiked by a cannula. However, there are shortcomings associated with that type of packaging including potential product contamination and extensive set-up-time. In response to that problem, a multi-layer plastic bottle was developed having a central layer which provided an oxygen barrier, therefore permitting the bottle to be pre-filled with food product which provided greater shelf-life and less spoilage. This type of plastic bottle utilizes a membrane which must be pierced so as to permit the commencement of the feeding process.
Unfortunately, three problems have plagued the prior art pre-filled industry which now experiences annual sales of over $500,000,000. The first problem involves the potential for contamination of the nutrition product by the conventional use of a tool or finger to pierce the heat-sealed membrane. The contamination of the product with bacteria from a non-sterilized tool or from the hands of a health care worker can result in the patient ingesting spoiled food product without his knowledge, since enteral feeding involves no sensation of taste to warn the patient of the spoilage.
The second problem involves the actual piercing of the heat-sealed membrane by a cannula. The health care worker after insertion of a cannula through a closure on existing enteral nutritional product containers is unable to determine the extent to which, if any, the seal has been broken. This problem is acerbated by the physical makeup of enteral nutritional products. Enteral nutritional products are dissimilar from fluids introduced by intravenous feeding primarily due to the presence of minerals and other solids which tend to form a sediment which settles to the bottom of the inverted container during feeding. Additionally, enteral nutritional products are more viscous than intravenous solutions. Due to the physical properties of enteral nutritional products, there is a strong tendency for the food product to deform the broken seal, perhaps even partially occluding the opening, and thus restricting the amount of food product which is being dispensed to the patient. In fact, the possibility exists for complete occlusion of the opening and hence termination of the feeding process.
The third problem relates to the cannulation process, which periodically requires the introduction of a small amount of atmospheric air to preclude the establishment of a vacuum in the system, which would also terminate the feeding process. This problem has traditionally been overcome by the providing of a valve means to introduce atmospheric air into the enteral nutritional product container. A problem arises if the air which is being introduced into the container enters the cannula, instead of rising through the food product, such that aspiration takes place.
Ported closures are well known, an example of which is Steidley, U.S. Pat. No. 4,022,258 which discloses a closure for surgical irrigation fluid containers. Steidley discloses a large spiked member which can pierce a plastic cap having an annular top wall which functions as the original closure for the bottle of surgical irrigation fluid, thereby obviating the need for a heat-sealed membrane. However, Steidley does not address the unique problems associated with the physical composition of enteral nutritional products.
It is thus apparent that the need exists for an improved closure for a pre-filled, membrane-sealed enteral nutritional product container which permits the use of "spike"-type delivery sets which provides system seal integrity, as well as permitting the opening of the nutritional products container in a single-action motion while maintaining product sterility.